       "PixelType" (get-pixel-type)
       "Positions" (max 1 (count (:positions settings)))
       "Prefix" (if (:save settings) (:prefix settings) "")
-      "ROI" (get-camera-roi)
+      "ROI" (JSONArray. (get-camera-roi))
       "Slices" (max 1 (count (:slices settings)))
       "SlicesFirst" (:slices-first settings)
       "Source" "Micro-Manager"

        super-channels (all-super-channels simple-channels 
                                           (get-camera-channel-names))
        ch-names (vec (map :name super-channels))]
     (mm/to-json {
      "BitDepth" (core getImageBitDepth)
      "Channels" (max 1 (count super-channels))
      "ChNames" ch-names
      "ChColors" (channel-colors simple-channels super-channels ch-names)
      "ChContrastMax" (repeat (count super-channels) 65536)
      "ChContrastMin" (repeat (count super-channels) 0)
      "Comment" (:comment settings)
      "ComputerName" (.. InetAddress getLocalHost getHostName)
      "Depth" (core getBytesPerPixel)

      "GridRow" 0
      "Height" (core getImageHeight)
      "Interval_ms" (:interval-ms settings)
      "CustomIntervals_ms" (JSONArray. (or (:custom-intervals-ms settings) []))
      "IJType" (get-IJ-type depth)
      "KeepShutterOpenChannels" (:keep-shutter-open-channels settings)
      "KeepShutterOpenSlices" (:keep-shutter-open-slices settings)
